It’s rare for a crime drama to hold its secret right up to the final episode, but Broadchurch (UTV, Monday) did. And it didn’t wait until the last few minutes to reveal whodunnit, so there was time to explore the impact of the events on the people involved and the wider community in the small Dorset village where it was set – because that’s what this clever, perfectly paced police procedural was all about and why it was so watchable. And also why, right from the start, eight weeks ago, it seemed like a British version of the Scandinavian thrillers that we’re hoovering up with such determination.

Danny Latimer’s killer – no spoilers: that would be mean if you’ve recorded it and waited this long – was unmasked early in the final episode, leaving the detective duo, an inspired pairing of Olivia Colman and David Tennant, some of their best scenes as they dealt with the fallout.

It also gave time for Chris Chibnall, its writer, to leave some puzzles behind (such as how truthful the killer was about what happened that night and what will happen to his wife). And because the characters had been so well developed they were satisfying instead of loose-end annoying.

At least
Tennant’s
character was only given a mysterious brain condition in
Broadchurch
. (He’s set to make a rapid recovery: the drama has been such a rampaging ratings winner that it has been recommissioned already.) In
The Politician’s Husband
(BBC One, Thursday) he was given such a head of blond highlights that he looked more like a 1980s boy-band singer than a government minister.

It’s rare for a hairdo to be so distracting in a classy drama, but Tennant is always so recognisably himself and isn’t usually the sort of actor to go in for daft dos – stubble, yes: he looked like an unmade bed in
Broadchurch
– but blond, no. But then so much in
The Politician’s Husband
was spelled out in
such
plodding detail that Tennant’s quiff was a welcome distraction.

It’s a companion piece, written by Paula Milne, who wrote the award-winning 1990s drama
The Politician’s Wife
. That had Juliet Stevenson as the wife who discovers that her Conservative politician husband (played by Trevor Eve) is having an affair with an escort (Minnie Driver).

Instead of meekly standing by her man for the cameras – a familiar sight on the news at the time – she ditches her floral skirt and Aga lifestyle, puts on a sharp suit and plots revenge.

This new version is all about revenge, too, but this time a straightforward,
House of Cards
-type power-fuelled takedown.

Tennant is Aiden Hoynes, a government minister who, with his junior-minister wife, Freya (Emily Watson), is part of a political golden couple until he resigns from cabinet in a leadership bid that is thwarted by his best friend and cabinet colleague, Bruce Babbish. A reshuffle ensues, and she is promoted to minister while Aiden takes to wearing a tracksuit (TV code for loser), doing the school run (code for a man with nothing better to do) and scheming. With his wife now at the centre of power – “out of his shadow” in large print in the tabloid headlines – and feeding him information, he can get on with plotting Babbish’s political demise.

“I’m not just your mole but your whore,” Freya says as he picks out her clothes for her first day as minister, as if she’s Eliza Dolittle getting a makeover instead of an already successful politician who, it’s safe to assume, knew that a nice pair of court shoes goes with a suit. So much was spelled out – disappointing in a drama of this calibre.
The Politician’s Husband
is about as subtle as Tennant’s highlights.

“To stay top dog you may have to unleash the bitch within,” Freya is advised. That’s episode two teed up, then.

But it is curious how often the behind-the-scenes shenanigans at Westminster are the stuff of serious drama on British TV (all that power-hungry scheming) while the denizens of Leinster House feature only in a comic, eejity way in Irish drama series, such as
An Crisis, Rásaí na Gaillimhe
or
Val Falvey TD
, where invariably they’re parochial cute hoors.

Those Ulster Scots folk are a canny – see, it’s catching – lot. Picking the comedian and Tyroneman Kevin McAleer to present
Our Friends in the North
(RTÉ One, Monday) – a series explaining, maybe even introducing, the Ulster Scot to viewers who might turn off at the sight of a marching band – was inspired. He’s gentle and calm, quips about being a Catholic pagan, and is hilarious. “They say on a clear day you can see Scotland. The last sighting was 1856.”

And he’s happy to admit he has his own cultural baggage: “The shamrock, the GAA . . . I like to think I’ve lost that along the way. It’s only hand luggage at this point, and I’d like to get rid of that.”

The idea of this series is that he travels around the North from his Omagh home: “Fifty miles up the road to Antrim. It’s a different world.” He visited pockets of Ulster Scots to try to understand people who, he says, he had always thought of as dour, hardworking, oatcake-eating Presbyterian types.

He found classes of children in kilts learning the Highland fling, marching bands following banners, lots of accordion playing and Ullans, a dialect that’s still spoken and, he was told, undergoing a revival. It really did seem like another country, and he was straightforward in his alienation from their culture and beliefs, admitting, “My own orange-versus-green cultural baggage was playing at the back of my head, but what I took away was the warm welcome.”

The most straightforward explanation he was given was: “We’re not Irish; we’re not English, either. The Ulster-Scots identity is something we can identify with.”

But, talking straight to camera, his face a study in genuine bafflement, he admitted that he was no nearer to understanding what makes the Ulster Scots tick: “I feel like I’m back to square one.”

Two episodes in, I was with him on that one. After a night out with another very welcoming Ulster-Scots community, at a folk concert in a hall, he said, “There’s not much sign of the 20th century: it’s a sing-song and a cup of tea and an early night. Sure what could be wrong with that?”